In the field of photography, there has been a long recognized need for convenient image printing and/or displaying after an image is captured. The users like to examine, store, share, edit, manage, and communicate the captured images in a timely fashion. Furthermore, it is highly desirable for the all functions to be provided in a compact system so that the users can use them a portable fashion.
Several commercial products have attempted to address the above needs: one of these product is the instant photographic cameras based on the silver halide photographic technologies. The images are captured by sensitized emulsion grains and the images are formed on a photographic paper. This product, however, does not provide the users the capabilities of storing, editing, managing, and electronically communicating the captured images.
FIG. 1 shows another type of commercial product comprising an electronic camera and a digital printer. The camera-printer system 5 comprises a camera 10 and a printer 40. In the configuration shown in FIG. 1, the camera 10 includes an image sensor 20, an image processing unit 30, and a microcontroller 50. It is understood that the image processing unit 30 and the microcontroller 50 can also be stand alone or inside the printer 40. The camera-printer system 5 may also include a user input and a display. A common image sensor 20 is in a charge-coupled device (CCD) configuration. A detailed diagram of a CCD sensor is shown in FIG. 2.
In a typical operation of the camera-printer system 5, the image of a scene is captured by the image sensor 20. The image sensor 20 comprises a plurality of light detecting elements 60. The photons from the original scene are captured by the two dimensional array of light detecting elements 60, the photons being absorbed by the light sensitive material in the light detecting elements 60. Electron charges are then generated by electronic excitations. The number of the electron charges within each light detecting element 60 is directly related to the number of photons being absorbed by the light detecting element 60. After the exposure of the scene is completed, the electron charges in the light detecting elements 60 are shifted to the CCD shift register 70. The electron charges in the CCD shift register 70 are then transferred to the output register 80 row by row in a sequential fashion. The electron charges, arranged in rows in the output register 80, are again sequentially shifted through amplifier 90 and to the analog-to-digital converter (A/DC) 100. The analog signals of the electron charges are converted to digital voltages at the A/DC 100, which together constitute the pixel values at each pixel of the two dimensional image file corresponding to the scene. The sequential pixel values output from the image sensor 20 are received by the image processing unit 30 as controlled by the microcontroller 50. The image data can then be processed, displayed can be transferred to the printer via a cable and a wireless port for printing.
The above described electronic camera printer system has the following disadvantages: first, the system is not compact; second, the electron charge transfer within and from the CCD image sensor are conducted in a sequential fashion, which is time consuming. Finally, in order to produce images, the digital output of the camera has to be transferred to a storage medium such as a floppy disk or electronic memory. This medium is used to transfer the images to a display device such as a monitor or to a separate printing device.